The invention relates to a constant velocity universal joint of the tripod type having an outer joint part provided with three circumferentially distributed, axially extending longitudinal recesses with circumferentially distributed opposed running faces, an inner joint part provided with three circumferentially distributed radial journals engaging the longitudinal recesses, with each of the journals being provided with roller members which are held substantially isogonally in the longitudinal recesses and which are held relative to the journals so as to be radially displaceable and angularly movable, with each roller member being rotatably supported on a roller carrier.
Simple tripod joints in the case of which the roller members are supported coaxially relative to the respective journal are disadvantageous in that, with an articulated joint, the oscillating axial movements of the rollers in the tracks do not take place in the form of clean rolling movements, but because of the angular position of the rollers relative to the direction of movement, they include a friction component as a result of which there occur considerable friction forces leading to axial vibration excitations out of the joint. It is therefore an improvement if, with an articulated joint, the roller members oscillate isogonally in a clean rolling movement in the longitudinal recesses, whereas the sliding movements of the radial displacement of the roller members on the journals and the angular movement of the roller members relative to the journals take place on pairs of faces which are independent of the longitudinal recesses.
From DE 31 03 172 C 2 and DE 38 03 340 A 1 there is known a joint in which an intermediate ring with a spherical segment face is radially movable on the cylindrical journal which engages a calotte face of a roller carrier. On the roller carrier, the roller member is supported in needles. With this design, production is very expensive because it is necessary to machine two pairs of faces sliding on each other, with one of them being designed as a ball/calotte combination.
From DE 28 31 044 A 1, in addition to the joint of the said type, there are known designs in the case of which the journals are provided with spherical heads which, on the one hand, are directly radially movable and engage bearing needles of the roller member and which, on the other hand, cooperate with a calotte-shaped inner face of an intermediate ring radially movable in the roller member. In the former case, the point contact between the ball head and bearing needles leads to an uncontrollable surface pressure, and in the latter case, the rotational support means for the rollers are designed as friction bearings only, with the production and assembly of the inner ring being complicated and expensive.
From DE 36 19 728 A 1 there is known a tripod joint in which the direct contact with the tracks of the outer joint part is established by linearly arranged rolling members which are held by a pivot head of rectangular shape if viewed radially. An essentially similar tripod joint is known from JP-A-59-40016, in which the tripod journals comprise spherical heads radially movably engaging internally cylindrical recesses in the pivot heads. In the former case there are provided purely axial roller assemblies as rolling members. In the latter case, balls especially held in continuous guiding means form the rolling members. Producing the pivot heads is expensive, and there is a need for expensive and sensitive connecting means between the pivot head and the spherical member. Below the spherical head, the journal cross-section is reduced which is disadvantageous from the point of view of strength.
From DE 37 16 962 A 1 there is known a joint in which an intermediate ring rotatably supported on the cylindrical journal by means of rolling members comprises a spherical outer face which is guided angularly movably and radially displaceably in an internally cylindrical face of the roller member. Essentially there are no rotary movements between the intermediate ring and the roller member. Producing this design is also expensive because the intermediate ring has to be provided with an accurate spherical sliding face, with the roller member having to comprise an accurately machined outer running face.